<?php

namespace Libs;

use CurlHandle;

/**
 * Aria2
 *
 * Library to control aria2c from PHP
 * using its jsonrpc API.
 *
 * @author KJ
 * @website https://kj2.me
 * @licence MIT
 */
class Aria2
{
    protected CurlHandle $ch;
    protected ?string $token;
    protected bool $batch = false;
    protected array $batch_list = [];

    /**
     * Constructor
     *
     * @param string      $server
     *                            Path to aria2's jsonrpc server.
     * @param string|null $token
     *                            (optional) Access token for aria2c API.
     */
    public function __construct(string $server = 'http://127.0.0.1:6800/jsonrpc', ?string $token = null)
    {
        $this->ch    = curl_init($server);
        $this->token = $token;
        curl_setopt_array($this->ch, [
            CURLOPT_POST           => true,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_HEADER         => false,
        ]);
    }

    /**
     * Allows starting a batch call.
     *
     * @return static
     */
    public function batch(): static
    {
        $this->batch = true;
        return $this;
    }

    /**
     * Returns whether it is in a batch call or not.
     *
     * @return bool
     */
    public function inBatch(): bool
    {
        return $this->batch;
    }

    /**
     * Sends a batch request.
     *
     * @return mixed
     */
    public function commit(): mixed
    {
        $data             = json_encode($this->batch_list);
        $this->batch      = false;
        $this->batch_list = [];
        $result           = $this->send($data);
        return json_decode($result);
    }

    /**
     * Sends a request to aria2c via jsonrpc.
     *
     * @param  string      $data
     * @return string|bool
     */
    protected function send(string $data): string|bool
    {
        curl_setopt($this->ch, CURLOPT_POSTFIELDS, $data);
        return curl_exec($this->ch);
    }

    /**
     * Magic to simplify work :).
     *
     * PHP methods are automatically converted into aria2 methods.
     *
     * aria2.addUri               => Aria2::addUri
     * aria2.addTorrent           => Aria2::addTorrent
     * aria2.getPeers             => Aria2::getPeers
     * aria2.addMetalink          => Aria2::addMetalink
     * aria2.remove               => Aria2::remove
     * aria2.pause                => Aria2::pause
     * aria2.forcePause           => Aria2::forcePause
     * aria2.pauseAll             => Aria2::pauseAll
     * aria2.forcePauseAll        => Aria2::forcePauseAll
     * aria2.unpause              => Aria2::unpause
     * aria2.unpauseAll           => Aria2::unpauseAll
     * aria2.forceRemove          => Aria2::forceRemove
     * aria2.changePosition       => Aria2::changePosition
     * aria2.tellStatus           => Aria2::tellStatus
     * aria2.getUris              => Aria2::getUris
     * aria2.getFiles             => Aria2::getFiles
     * aria2.getServers           => Aria2::getServers
     * aria2.tellActive           => Aria2::tellActive
     * aria2.tellWaiting          => Aria2::tellWaiting
     * aria2.tellStopped          => Aria2::tellStopped
     * aria2.getOption            => Aria2::getOption
     * aria2.changeUri            => Aria2::changeUri
     * aria2.changeOption         => Aria2::changeOption
     * aria2.getGlobalOption      => Aria2::getGlobalOption
     * aria2.changeGlobalOption   => Aria2::changeGlobalOption
     * aria2.purgeDownloadResult  => Aria2::purgeDownloadResult
     * aria2.removeDownloadResult => Aria2::removeDownloadResult
     * aria2.getVersion           => Aria2::getVersion
     * aria2.getSessionInfo       => Aria2::getSessionInfo
     * aria2.shutdown             => Aria2::shutdown
     * aria2.forceShutdown        => Aria2::forceShutdown
     * aria2.getGlobalStat        => Aria2::getGlobalStat
     * aria2.saveSession          => Aria2::saveSession
     * system.multicall           => Aria2::system_multicall
     * system.listMethods         => Aria2::system_listMethods
     * system.listNotifications   => Aria2::system_listNotifications
     *
     * @param  array<int,mixed> $arg
     * @return mixed
     */
    public function __call(string $name, array $arg): mixed
    {
        if (!is_null($this->token)) {
            array_unshift($arg, $this->token);
        }

        // Allow system methods (the last 3 on the list)
        if (strpos($name, '_') === false) { // if it doesn't contain underscores, it's an aria2 method command.
            $name = 'aria2.' . $name;
        } else {
            $name = str_replace('_', '.', $name);
        }

        $data = [
            'jsonrpc' => '2.0',
            'id'      => '1',
            'method'  => $name,
            'params'  => $arg,
        ];

        // Apply batch call if we are in one
        if ($this->batch) {
            $this->batch_list[] = $data;
            return $this;
        }

        $data     = json_encode($data);
        $response = $this->send($data);
        if ($response === false) {
            trigger_error(curl_error($this->ch));
        }

        return json_decode($response);
    }
}